Should Animals be used in Scientific Research?
In Paleocene oceans, sharks filled the empty niches left by aquatic reptiles, but it took coral reefs ten million years to begin to recover, . As Africa and India moved northward, the shrank, and in the late Paleocene and early Eocene, one of the last Tethyan anoxic events laid down Middle East oil, and the last Paleocene climate event is called the (“PETM”). The PETM has been the focus of a great deal of recent research because of its parallels to today’s industrial era, when carbon dioxide and other greenhouse gases are massively vented to the atmosphere, causing a warming atmosphere and acidifying oceans. The seafloor communities suffered a mass extinction and the PETM’s causes are uncertain, but the when the global ocean warmed sufficiently is a prominent hypothesis. Scientists also look to the usual suspects of volcanism, changes in oceanic circulation, and a bolide impact.
Should Animals Be Used In Medical Research Essays 1 …
Peter Ward led an effort to catalog the fossil record before and after Romer’s Gap, which found a dramatic that did not resume until about 340-330 mya. Romer’s Gap seems to have coincided with low-oxygen levels of the late Devonian and early Carboniferous. If coincided with a halt in colonization, just as the adaptation to breathing air was beginning, the obvious implication is that low oxygen levels hampered early land animals. Not just the lung had to evolve for the up-and-coming amphibians, but the entire chest cavity had to evolve to expand and contract while also allowing for a new mode of locomotion. When amphibians and splay-footed reptiles run, they cannot breathe, as their mechanics of locomotion prevent running and breathing at the same time. Even walking and breathing is generally difficult. This means that they cannot perform any endurance locomotion but have to move in short spurts. This is why today’s predatory amphibians and reptiles are ambush predators. They can only move in short bursts, and then have to stop, breathe, and recover their oxygen deficit. In short, they have no stamina. This limitation is called . The below image shows the evolutionary adaptations that led to overcoming Carrier's Constraint. Dinosaurs overcame it first, and it probably was related to their dominance and the extinction or marginalization of their competitors. (Source: Wikimedia Commons)
The genetic testing that has been performed on humanity in the past generation has shown that the founder group’s pattern of migration was to continually spread out, and once the original settlement covered the continents, people did not move much at all, at least until Europe began conquering the world (and there were some ). There is little sign of warfare in those early days of migration, and the leading hypothesis is that people moved to the next valley rather than be close enough to fight each other. Any conflict would have been easily resolved by moving farther out, where more easily killed animals lived. Also, in those virgin continents, people need not have roamed far to obtain food. Today, an !Kung woman will carry her child more than 7,000 kilometers before the child can walk for himself/herself. If an !Kung woman bears twins, it is her duty to pick which child to murder, because she cannot afford to carry two. That demonstrates the limitations of today’s hunter-gatherer lifestyle, but in those halcyonic days of invading virgin continents (which had to be the Golden Age of the Hunter-Gatherer), those kinds of practices probably waned and bands grew fast. When they they split, and the new group moved to new lands where the animals, again, never saw people before. Unlike the case with humans, there would not have been a grapevine so that animals told their neighbors about the new super-predator. The first time that those megafauna saw humans was probably their last time. It is very likely, just as with all predators for all time, and as can be seen with historical hunting events such or , that those bands soon took to killing animals, harvesting the best parts, and moving on. To them it would not have been a “blitzkrieg,” but more like kids in candy stores. After a few thousand years of grabbing meat whenever the fancy took them, or perhaps less, those halcyonic days were over as the far coasts of Australia were reached and the easy meat was gone. When that land bridge formed to Tasmania about 43 kya, people crossed and were able to , until all the megafauna was gone on Tasmania. They also may have worked their way through the food chain, in which the first kills were the true mother lode. Nobody even deigned to raise a spear at anything less than a until they were gone. Then they started killing smaller prey, which eventually did wise up and were harder to kill, so humans had to work at it again and the brief golden age was over. The as they shaped the new continent to their liking, maybe recreating the savanna conditions that they left in Africa, may have also been used to flush out animals if they began to avoid humans.